Dehumidifying device



Oct. 26, 1965 H. FORWALD 3,213,937

DEHUMIDIFYING DEVICE Filed Oct. 21, 1965 KIA United States Patent 3,213,937 DEHUMIDIFYING DEVICE Haakon Forwald, Ludvika, Sweden, assignor to Allmanna Svenska Elektriska Aktiebolaget, Vasteras, Sweden, a Swedish corporation Filed Oct. 21, 1963, Ser. No. 317,678 Claims priority, application Sweden, Nov. 1, 1962, 11,724/ 62 5 Claims. (Cl. 165-132) This invention relates to a dehumidifier for high pressure gas and more specifically relates to a dehumidifier for dehumidifying the high pressure air for a compressed air circuit breaker.

In accordance with the invention, an auxiliary chamber is hydraulically connected between upper and lower portions of a high pressure gas container. An auxiliary cooling means which may be of simple and inexpensive construction is then provided for the auxiliary chamber so that the temperature of the auxiliary chamber is reduced. This will then force drying of the gas within the auxiliary chamber and circulation of new gas from the main container to the auxiliary chamber so that cooling and drying continuously occurs Without separate fans or chemical preparations directly associated with the main volume of compressed gas.

Accordingly, a primary object of this invention is to provide a novel dehumidifying system for compressed gas tanks.

Another object of this invention is to provide a novel dehumidifier for compressed gas which is simple in structure and is inexpensive.

These and other objects of the invention will become apparent from the following description when taken in connection with the drawings in which:

FIGURE 1 illustrates a first embodiment of the invention with the auxiliary cooling chamber shown in crosssection.

FIGURE 2 is similar to FIGURE 1 and shows an embodiment of the invention where the auxiliary cooling chamber is provided with an expansion nozzle for cooling.

Referring first to FIGURE 1, I have shown therein a compressed gas tank of any suitable type which is supplied with gas under pressure through a valve '11 in an input conduit 12. Suitable outlet conduits (not shown) are then provided in tank 10 and are connected to those systems requiring the high pressure gas under pressure. By way of example, tank 10 could be connected to a compressed air circuit breaker in the usual manner.

In accordance with the invention, upper and lower regions of an auxiliary chamber 13 are permanently connected to respective upper and lower regions of tank 10 by upper and lower conduits 14 and 15 respectively. Thus, the pressure within chamber 13 will be the same as the pressure within chamber 10. However, the volume of chamber 13 may be substantially smaller than the volume of chamber '10. Suitable valve members 16 and 17 may then be placed in conduits 14 and 15 for use during defrosting as will be described hereinafter.

An auxiliary cooling means is then contained within tank 13 which is comprised of an elongated metallic member 18 which has cooling fins such as fins 19 and 20 radiating therefrom. A fluid conduit 21 is then embedded in member 18 and passes through tank 13 in a sealed manner to a fluid circulating means and heat exchanger system 22. System 22 will then cause a small volume of cooling fluid to circulate through tube 21 so that the interior of chamber 13 is cooled, for example, by the order of 10 C. below the temperature of the gas in container '10. Where a total gas volume of 3 cubic meters is to be cooled, it has been found that less than 50 watts of power is sufiicient for the cooling system.

3,213,937 Patented Oct; 26, 1965 A drainage tube 23 having an outlet valve 24 is then provided at the bottom of container 13, for draining condensed moisture from the container 13 at suitable intervals.

In operation, the compressed gas within container 13 will be cooled and fall toward the bottom of container 13. This creates suflicient pressure to cause circulation of air from tank 10, through conduit 14, container 13, and conduit 15. If the gas coming into container 13 has a sufficiently high relative humidity (higher than some predetermined value which is to be prevented) condensation takes place on cooling fins 19 and 20. This decreases the absolute humidity of gas going back into tank 10.

If, for example, the relative humidity in tank 10 at the beg-inning of the process is this can be reduced to 50% to 60% by holding container 13 at a 10 C. lower temperature than the temperature of tank '10.

The condensate formed will then run down flanges 19 and 20, and, after sufficient accumulation, can be drained away through the drainage member 23. This accumulation can be observed through a suitable window (not shown) in container 13.

During frosting conditions, it is necessary to remove ice and frost from the fins 19 and 20. For this operation, valves 16 and '17 are closed and the chamber 13 is heated and drained. Thereafter, the valves 16 and 17 are reopened and the dehumidifying action continued.

FIGURE 2 is similar to FIGURE 1 but shows the use of an expansion cooling system. Thus, in FIGURE 2, the cooling member 18 is provided with an opening 30 therethrough which has a nozzle 31 at the upper end thereof. A source of compressed air is then connected to conduit 32 which is in turn connected to pressure control means 33 which applies a suitable gas pressure to nozzle 31. In operation, gas passing into channel 30 is expanded and thus cooled at nozzle 31 so the interior of chamber 13 may be suitably cooled.

Although -I have described preferred embodiments of my novel invention, many variations and modifications will now be apparent to those skilled in the art, and I prefer therefore to be limited not by the specific disclosure herein but only by the appended claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. In combination with a compressed gas container, a dehumidifier therefor comprising an auxiliary container, an auxiliary cooling means, and a first and second conduit; said first conduit being connected between respective portions adjacent the tops of said gas container and said auxiliary container; said second conduit being connected between respective portions adjacent the bottoms of said gas container and said auxiliary container; said auxiliary cooling means being connected to said auxiliary container in heat exchange relationship for cooling gas in the interior of said auxiliary container, whereby to produce circulation of gas through said first conduit from the gas container to the auxiliary container and through the second conduit from the auxiliary container to the gas container.

2. The dehumidifier substantially as set forth in claim 1 wherein the ends of each of the conduits are substantially at the same level.

3. The dehumidifier substantially as set forth in claim 1 which includes first and second valve members connected in said first and second conduits respectively for selectively shutting off communication between the interiors of said compressed gas container and auxiliary container, respectively.

4. The dehumidifier substantially as set forth in claim 1 which further includes a drainage member connected in the bottom of said auxiliary container.

5. The dehumidifier substantially as set forth in claim 1 wherein said cooling means includes a conductive member having extending fins; said conductive member being contained within said auxiliary chamber.

References Cited by the Examiner UNITED STATES PATENTS 7/25 Rodriquez 165132 X 7/31 Hartenstein 165-132 X 2/38 Gettleman 165108 12/44 Wineman 165-132 X 8/53 Brown 165-110 4 2,935,856 5/60 Gifford 6293 3,050,954 8/62 ROySe 6293 FOREIGN PATENTS 583,786 9/33 Germany.

ROBERT A. OLEARY, Primary Examiner.

KENNETH W. SPRAGUE, CHARLES SUKALO, PERCY L. PATRICK, FREDERICK L. MATTESON,

JR., Examiners. 

1. IN COMBINATION WITH A COMPRESSED GAS CONTAINER, A DEHUMIDIFIER THEREFOR COMPRISING AN AUXILIARY CONTAINER, AN AUXILIARY COOLING MEANS, AND A FIRST AND SECOND CONDUIT; SAID FIRST CONDUIT BEING CONNECTED BETWEEN RESPECTIVE PORTIONS ADJACENT THE TOPS OF SAID GAS CONTAINER AND SAID AUXILIARY CONTAINER; SAID SECOND CONDUIT BEING CONNECTED BETWEEN RESPECTIVE PORTIONS ADJACENT THE BOTTOMS OF SAID GAS CONTAINER AND SAID AUXILIARY CONTAINER; SAID AUXILIARY COOLING MEANS BEING CONNECTED TO SAID AUXILIARY CONTAINER IN HEAT EXCHANGE RELATIONSHIP FOR COOLING GAS IN 